431220021 has 4 divisors (see below), whose sum is σ = 574960032. Its totient is φ = 287480012.

The previous prime is 431220019. The next prime is 431220059. The reversal of 431220021 is 120022134.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 431220021 - 2¹ = 431220019 is a prime.

It is a super-2 number, since 2×431220021² = 371901413022480882, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (431220121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71870001 + ... + 71870006.

It is an arithmetic number, because the mean of its divisors is an integer number (143740008).

Almost surely, 2^431220021 is an apocalyptic number.

It is an amenable number.

431220021 is a deficient number, since it is larger than the sum of its proper divisors (143740011).

431220021 is a wasteful number, since it uses less digits than its factorization.

431220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143740010.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 431220021 is about 20765.8378352524. The cubic root of 431220021 is about 755.4973966102.

Adding to 431220021 its reverse (120022134), we get a palindrome (551242155).

The spelling of 431220021 in words is "four hundred thirty-one million, two hundred twenty thousand, twenty-one".